Muscle strains are very common in dogs,
especially performance dogs. The extreme bursts of energy such as in
agility can cause this. Eccentric contraction such as going down an
incline ie. off dog walk, or teeter in agility. Muscles that cross two
joints are more susceptible such as some of the hip muscles.
Chiropractors that are board certified in animal chiropractic are very
keen to these issues and can usually palpate the injury effectively.
Rehab, stretches, and adjustments will speed recovery.